Subspecialization within default mode nodes characterized in 10,000 UK Biobank participants

Abstract

SignificanceThe default mode network (DMN) encompasses supramodal association areas involved in higher-order cognition. One speculation is that this neural system is important for brain-wide information flow. We tested this account by exploring whether DMN patterns are informative about functional coupling or structural associations in the rest of the brain. Our multimodal pattern analysis findings highlight how the DMN nodes are fractionated: In specific subnodes, gray-matter morphology was linked to fiber tracts from the hippocampus in the medial temporal limbic system. In adjacent subnodes, fluctuations in neural activity were linked to between-network connectivity shifts. Such a mosaic architecture may be a prerequisite for many of the roles the DMN may play in advanced cognitive processes.

Bipartite functional fractionation within the default network supports disparate forms of internally oriented cognition

“…Recent advances in mapping the human cortex have discovered a clear gradient of structural and functional features that spans across the sensory-motoric system and the multimodal system, found in both humans and non-human primates (10,12,13,(43)(44)(45). An evident neurocognitive dimension of 'internal vs. external preference' underlies this cortical gradienton one extreme of the spectrum, the cortical regions are highly modality-specific (e.g., the primary visual/auditory cortex; 10), respond to external events occurring here and now (i.e., showing narrow spatiotemporal receptive fields; 46), and prefers concrete, perceivable stimuli to abstracted, conceptual stimuli (47).…”

The heterogeneous functional architecture of the posteromedial cortex is associated with selective functional connectivity differences in Alzheimer's disease

“…Yet, the PMC is often treated as having a homogenous functional architecture in studies of the DMN, despite its diverse patterns of functional connectivity (Y. Zhang et al, ). Recent work characterising the functional architecture of the PMC has shown that it consists of several different functional subdivisions that are associated with multiple large‐scale brain networks at rest (Kernbach et al, ; Leech, Braga, & Sharp, ; S. Zhang & Li, ). In particular, the posterior cingulate cortex (PCC), which lies in the medial part of the inferior parietal lobe, exhibits distinct cytoarchitectonics with functional separation into dorsal and ventral areas (Leech, Kamourieh, Beckmann, & Sharp, ; Vogt, Vogt, & Laureys, ).…”

“…Zhang et al, 2014). Recent work characterising the functional architecture of the PMC has shown that it consists of several different functional subdivisions that are associated with multiple large-scale brain networks at rest (Kernbach et al, 2018;Leech, Braga, & Sharp, 2012;S. Zhang & Li, 2012).…”

Beyond Consensus: Embracing Heterogeneity in Curated Neuroimaging Meta-Analysis

“…Both sub-systems might spatially overlap or inter-digitate across multiple brain regions (Andrews-Hanna et al, 2014;Rodrigo and Buckner, 2017), which would be challenging to ALE without assuming prior knowledge of the sub-systems ( Figure 1). Furthermore, specific default network fractionation details differed across studies Mayer et al 2010;Humphreys et al, 2015;Kernbach et al, 2018), so application of the author-topic model might potentially clarify sub-systems subserving self-generated thought.…”